Observation of Laser Power Amplification in a Self-Injecting Laser Wakefield Accelerator

Physical Review Letters 120 (2018)

MJV Streeter, S Kneip, MS Bloom, RA Bendoyro, O Chekhlov, AE Dangor, A Döpp, CJ Hooker, J Holloway, J Jiang, NC Lopes, H Nakamura, PA Norreys, CAJ Palmer, PP Rajeev, J Schreiber, DR Symes, M Wing, SPD Mangles, Z Najmudin

© 2018 American Physical Society. We report on the depletion and power amplification of the driving laser pulse in a strongly driven laser wakefield accelerator. Simultaneous measurement of the transmitted pulse energy and temporal shape indicate an increase in peak power from 187±11 TW to a maximum of 318±12 TW after 13 mm of propagation in a plasma density of 0.9×1018 cm-3. The power amplification is correlated with the injection and acceleration of electrons in the nonlinear wakefield. This process is modeled by including a localized redshift and subsequent group delay dispersion at the laser pulse front.

Single-shot frequency-resolved optical gating for retrieving the pulse shape of high energy picosecond pulses.

The Review of scientific instruments 89 (2018) 103509-

R Aboushelbaya, AF Savin, L Ceurvorst, J Sadler, PA Norreys, AS Davies, DH Froula, A Boyle, M Galimberti, P Oliveira, B Parry, Y Katzir, K Glize

Accurate characterization of laser pulses used in experiments is a crucial step to the analysis of their results. In this paper, a novel single-shot frequency-resolved optical gating (FROG) device is described, one that incorporates a dispersive element which allows it to fully characterize pulses up to 25 ps in duration with a 65 fs per pixel temporal resolution. A newly developed phase retrieval routine based on memetic algorithms is implemented and shown to circumvent the stagnation problem that often occurs with traditional FROG analysis programs when they encounter a local minimum.

AWAKE readiness for the study of the seeded self-modulation of a 400GeV proton bunch


P Muggli, E Adli, R Apsimon, F Asmus, R Baartman, A-M Bachmann, MB Marin, F Batsch, J Bauche, VKB Olsen, M Bernardini, B Biskup, EB Vinuela, A Boccardi, T Bogey, T Bohl, C Bracco, F Braunmuller, S Burger, G Burt, S Bustamante, B Buttenschoen, A Butterworth, A Caldwell, M Cascella, E Chevallay, M Chung, H Damerau, L Deacon, A Dexter, P Dirksen, S Doebert, J Farmer, V Fedosseev, T Feniet, G Fior, R Fiorito, R Fonseca, F Friebel, P Gander, S Gessner, I Gorgisyan, AA Gorn, O Grulke, E Gschwendtner, A Guerrero, J Hansen, C Hessler, W Hofle, J Holloway, M Huther, M Ibison, MR Islam, L Jensen, S Jolly, M Kasim, F Keeble, S-Y Kim, F Kraus, A Lasheen, T Lefevre, G LeGodec, Y Li, S Liu, N Lopes, KV Lotov, M Martyanov, S Mazzoni, DM Godoy, O Mete, VA Minakov, R Mompo, J Moody, MT Moreira, J Mitchell, C Mutin, P Norreys, E Oz, E Ozturk, W Pauw, A Pardons, C Pasquino, K Pepitone, A Petrenko, S Pitmann, G Plyushchev, A Pukhov, K Rieger, H Ruhl, J Schmidt, IA Shalimova, E Shaposhnikova, P Sherwood, L Silva, AP Sosedkin, R Speroni, RI Spitsyn, K Szczurek, J Thomas, PV Tuev, M Turner, V Verzilov, J Vieira, H Vincke, CP Welsch, B Williamson, M Wing, G Xia, H Zhang, AWAKE Collaboration

Hydrodynamic optical-field-ionized plasma channels.

Physical review. E 97 (2018) 053203-

RJ Shalloo, C Arran, L Corner, J Holloway, J Jonnerby, R Walczak, HM Milchberg, SM Hooker

We present experiments and numerical simulations which demonstrate that fully ionized, low-density plasma channels could be formed by hydrodynamic expansion of plasma columns produced by optical field ionization. Simulations of the hydrodynamic expansion of plasma columns formed in hydrogen by an axicon lens show the generation of 200 mm long plasma channels with axial densities of order n_{e}(0)=1×10^{17}cm^{-3} and lowest-order modes of spot size W_{M}≈40μm. These simulations show that the laser energy required to generate the channels is modest: of order 1 mJ per centimeter of channel. The simulations are confirmed by experiments with a spherical lens which show the formation of short plasma channels with 1.5×10^{17}cm^{-3}≲n_{e}(0)≲1×10^{18}cm^{-3} and 61μm≳W_{M}≳33μm. Low-density plasma channels of this type would appear to be well suited as multi-GeV laser-plasma accelerator stages capable of long-term operation at high pulse repetition rates.

Layout considerations for a future electron plasma research accelerator facility EuPRAXIA

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment (2018)

PA Walker, RW Assmann, R Brinkmann, E Chiadroni, U Dorda, M Ferrario, D Kocon, B Marchetti, L Pribyl, A Specka, R Walczak

© 2018 Elsevier B.V. The Horizon 2020 Project EuPRAXIA (“European Plasma Research Accelerator with eXcellence In Applications”) is preparing a conceptual design for a highly compact and cost-effective European facility with multi-GeV electron beams using plasma as the acceleration medium. The design includes two user areas: one for FEL science and one for High Energy Physics (HEP) detector development and other pilot applications. The accelerator facility will be based on a laser and/or a beam driven plasma acceleration approach. This contribution introduces layout considerations of the future plasma accelerator facilities in the context of EuPRAXIA. It compares conventional and novel plasma accelerator facility requirements and presents potential layouts for the future site. Together with performance analysis, cost effectiveness, and targeted user cases of the individual configurations, such layout studies will later enable a ranking of potential configurations. Based on this information the optimal combination of technologies will be defined for the 2019 conceptual design report of the EuPRAXIA facility.

Channel optimization of high-intensity laser beams in millimeter-scale plasmas.

Physical review. E 97 (2018) 043208-

L Ceurvorst, A Savin, N Ratan, MF Kasim, J Sadler, PA Norreys, H Habara, KA Tanaka, S Zhang, MS Wei, S Ivancic, DH Froula, W Theobald

Channeling experiments were performed at the OMEGA EP facility using relativistic intensity (>10^{18}W/cm^{2}) kilojoule laser pulses through large density scale length (∼390-570 μm) laser-produced plasmas, demonstrating the effects of the pulse's focal location and intensity as well as the plasma's temperature on the resulting channel formation. The results show deeper channeling when focused into hot plasmas and at lower densities, as expected. However, contrary to previous large-scale particle-in-cell studies, the results also indicate deeper penetration by short (10 ps), intense pulses compared to their longer-duration equivalents. This new observation has many implications for future laser-plasma research in the relativistic regime.

Advantages to a diverging Raman amplifier

Communications Physics 1 (2018)

JD Sadler, LO Silva, RA Fonseca, K Glize, MF Kasim, A Savin, R Aboushelbaya, MW Mayr, B Spiers, RHW Wang, R Bingham, RMGM Trines, PA Norreys

Observation of extremely strong shock waves in solids launched by petawatt laser heating

PHYSICS OF PLASMAS 24 (2017) ARTN 083115

KL Lancaster, APL Robinson, J Pasley, P Hakel, T Ma, K Highbarger, FN Beg, SN Chen, RL Daskalova, RR Freeman, JS Green, H Habara, P Jaanimagi, MH Key, J King, R Kodama, K Krushelnick, H Nakamura, M Nakatsutsumi, AJ MacKinnon, AG MacPhee, RB Stephens, L Van Woerkom, PA Norreys

Excitation and Control of Plasma Wakefields by Multiple Laser Pulses.

Physical review letters 119 (2017) 044802-

J Cowley, C Thornton, C Arran, RJ Shalloo, L Corner, G Cheung, CD Gregory, SPD Mangles, NH Matlis, DR Symes, R Walczak, SM Hooker

We demonstrate experimentally the resonant excitation of plasma waves by trains of laser pulses. We also take an important first step to achieving an energy recovery plasma accelerator by showing that a plasma wave can be damped by an out-of-resonance trailing laser pulse. The measured laser wakefields are found to be in excellent agreement with analytical and numerical models of wakefield excitation in the linear regime. Our results indicate a promising direction for achieving highly controlled, GeV-scale laser-plasma accelerators operating at multikilohertz repetition rates.

Attosecond-scale absorption at extreme intensities

PHYSICS OF PLASMAS 24 (2017) ARTN 113103

AF Savin, AJ Ross, M Serzans, RMGM Trines, L Ceurvorst, N Ratan, B Spiers, R Bingham, APL Robinson, PA Norreys

Scattering length monitoring at the SNO plus detector

Journal of Physics : Conference Series Institute of Physics (IoP) 888 (2017)

S Langrock, J Lidgard, E Turner, L Segui, A Reichold, JR Wilson, SNO Collaboration

Dense plasma heating by crossing relativistic electron beams.

Physical review. E 95 (2017) 013211-

N Ratan, NJ Sircombe, L Ceurvorst, J Sadler, MF Kasim, J Holloway, MC Levy, R Trines, R Bingham, PA Norreys

Here we investigate, using relativistic fluid theory and Vlasov-Maxwell simulations, the local heating of a dense plasma by two crossing electron beams. Heating occurs as an instability of the electron beams drives Langmuir waves, which couple nonlinearly into damped ion-acoustic waves. Simulations show a factor 2.8 increase in electron kinetic energy with a coupling efficiency of 18%. Our results support applications to the production of warm dense matter and as a driver for inertial fusion plasmas.

Nonlinear parametric resonance of relativistic electrons with a linearly polarized laser pulse in a plasma channel

Physics of Plasmas 24 (2017)

TW Huang, CT Zhou, APL Robinson, B Qiao, AV Arefiev, PA Norreys, XT He, SC Ruan

© 2017 Author(s). The direct laser-acceleration mechanism, nonlinear parametric resonance, of relativistic electrons in a linearly polarized laser-produced plasma channel is examined by a self-consistent model including the relativistic laser dispersion in plasmas. Nonlinear parametric resonance can be excited, and the oscillation amplitude of electrons grows exponentially when the betatron frequency of electron motion varies roughly twice the natural frequency of the oscillator. It is shown analytically that the region of parametric resonance is defined by the self-similar parameter ne/nca0. The width of this region decreases with ne/nca0, but the energy gain and oscillation amplitude increases. In this regime, the electron transverse momentum grows faster than that in the linear classical resonance regime.

Machine learning applied to proton radiography of high-energy-density plasmas.

Physical review. E 95 (2017) 043305-

NFY Chen, MF Kasim, L Ceurvorst, N Ratan, J Sadler, MC Levy, R Trines, R Bingham, P Norreys

Proton radiography is a technique extensively used to resolve magnetic field structures in high-energy-density plasmas, revealing a whole variety of interesting phenomena such as magnetic reconnection and collisionless shocks found in astrophysical systems. Existing methods of analyzing proton radiographs give mostly qualitative results or specific quantitative parameters, such as magnetic field strength, and recent work showed that the line-integrated transverse magnetic field can be reconstructed in specific regimes where many simplifying assumptions were needed. Using artificial neural networks, we demonstrate for the first time 3D reconstruction of magnetic fields in the nonlinear regime, an improvement over existing methods, which reconstruct only in 2D and in the linear regime. A proof of concept is presented here, with mean reconstruction errors of less than 5% even after introducing noise. We demonstrate that over the long term, this approach is more computationally efficient compared to other techniques. We also highlight the need for proton tomography because (i) certain field structures cannot be reconstructed from a single radiograph and (ii) errors can be further reduced when reconstruction is performed on radiographs generated by proton beams fired in different directions.

The Coherent Combination of Fibre Lasers - Towards Realistic Applications


P Tudor, L Corner, R Walczak, AIP

Quantitative shadowgraphy and proton radiography for large intensity modulations.

Physical review. E 95 (2017) 023306-

MF Kasim, L Ceurvorst, N Ratan, J Sadler, N Chen, A Sävert, R Trines, R Bingham, PN Burrows, MC Kaluza, P Norreys

Shadowgraphy is a technique widely used to diagnose objects or systems in various fields in physics and engineering. In shadowgraphy, an optical beam is deflected by the object and then the intensity modulation is captured on a screen placed some distance away. However, retrieving quantitative information from the shadowgrams themselves is a challenging task because of the nonlinear nature of the process. Here, we present a method to retrieve quantitative information from shadowgrams, based on computational geometry. This process can also be applied to proton radiography for electric and magnetic field diagnosis in high-energy-density plasmas and has been benchmarked using a toroidal magnetic field as the object, among others. It is shown that the method can accurately retrieve quantitative parameters with error bars less than 10%, even when caustics are present. The method is also shown to be robust enough to process real experimental results with simple pre- and postprocessing techniques. This adds a powerful tool for research in various fields in engineering and physics for both techniques.

Optimization of plasma amplifiers.

Physical review. E 95 (2017) 053211-

JD Sadler, RMGM Trines, M Tabak, D Haberberger, DH Froula, AS Davies, S Bucht, LO Silva, EP Alves, F Fiúza, L Ceurvorst, N Ratan, MF Kasim, R Bingham, PA Norreys

Plasma amplifiers offer a route to side-step limitations on chirped pulse amplification and generate laser pulses at the power frontier. They compress long pulses by transferring energy to a shorter pulse via the Raman or Brillouin instabilities. We present an extensive kinetic numerical study of the three-dimensional parameter space for the Raman case. Further particle-in-cell simulations find the optimal seed pulse parameters for experimentally relevant constraints. The high-efficiency self-similar behavior is observed only for seeds shorter than the linear Raman growth time. A test case similar to an upcoming experiment at the Laboratory for Laser Energetics is found to maintain good transverse coherence and high-energy efficiency. Effective compression of a 10kJ, nanosecond-long driver pulse is also demonstrated in a 15-cm-long amplifier.

Robustness of raman plasma amplifiers and their potential for attosecond pulse generation


JD Sadler, M Sliwa, T Miller, MF Kasim, N Ratan, L Ceurvorst, A Savin, R Aboushelbaya, PA Norreys, D Haberberger, AS Davies, S Bucht, DH Froula, J Vieira, RA Fonseca, LO Silva, R Bingham, K Glize, RMGM Trines

Horizon 2020 EuPRAXIA design study


PA Walker, PD Alesini, AS Alexandrova, MP Anania, NE Andreev, I Andriyash, A Aschikhin, RW Assmann, T Audet, A Bacci, IF Barna, A Beaton, A Beck, A Beluze, A Bernhard, S Bielawski, FG Bisesto, J Boedewadt, F Brandi, O Bringer, R Brinkmann, E Bruendermann, M Buescher, M Bussmann, GC Bussolino, A Chance, JC Chanteloup, M Chen, E Chiadroni, A Cianchi, J Clarke, J Cole, ME Couprie, M Croia, B Cros, J Dale, G Dattoli, N Delerue, O Delferriere, P Delinikolas, J Dias, U Dorda, K Ertel, AF Pousa, M Ferrario, F Filippi, J Fils, R Fiorito, RA Fonseca, M Galimberti, A Gallo, D Garzella, P Gastinel, D Giove, A Giribono, LA Gizzi, FJ Gruener, AF Habib, LC Haefner, T Heinemann, B Hidding, BJ Holzer, SM Hooker, T Hosokai, A Irman, DA Jaroszynski, S Jaster-Merz, C Joshi, MC Kaluza, M Kando, OS Karger, S Karsch, E Khazanov, D Khikhlukha, A Knetsch, D Kocon, P Koester, O Kononenko, G Korn, I Kostyukov, L Labate, C Lechner, WP Leemans, A Lehrach, FY Li, X Li, V Libov, A Lifschitz, V Litvinenko, W Lu, AR Maier, V Malka, GG Manahan, SPD Mangles, B Marchetti, A Marocchino, AM De la Ossa, JL Martins, F Massimo, F Mathieu, G Maynard, TJ Mehrling, AY Molodozhentsev, A Mosnier, A Mostacci, AS Mueller, Z Najmudin, PAP Nghiem, F Nguyen, P Niknejadi, J Osterhoff, D Papadopoulos, B Patrizi, R Pattathil, V Petrillo, MA Pocsai, K Poder, R Pompili, L Pribyl, D Pugacheva, S Romeo, AR Rossi, E Roussel, AA Sahai, P Scherkl, U Schramm, CB Schroeder, J Schwindling, J Scifo, L Serafini, ZM Sheng, LO Silva, T Silva, C Simon, U Sinha, A Specka, MJV Streeter, EN Svystun, D Symes, C Szwaj, G Tauscher, AGR Thomas, N Thompson, G Toci, P Tomassini, C Vaccarezza, M Vannini, JM Vieira, F Villa, C-G Wahlstrom, R Walczak, MK Weikum, CP Welsch, C Wiemann, J Wolfenden, G Xia, M Yabashi, L Yu, J Zhu, A Zigler, IOP

High flux, beamed neutron sources employing deuteron-rich ion beams from D<inf>2</inf>O-ice layered targets

Plasma Physics and Controlled Fusion 59 (2017)

A Alejo, AG Krygier, H Ahmed, JT Morrison, RJ Clarke, J Fuchs, A Green, JS Green, D Jung, A Kleinschmidt, Z Najmudin, H Nakamura, P Norreys, M Notley, M Oliver, M Roth, L Vassura, M Zepf, M Borghesi, RR Freeman, S Kar

© 2017 IOP Publishing Ltd. A forwardly-peaked bright neutron source was produced using a laser-driven, deuteron-rich ion beam in a pitcher-catcher scenario. A proton-free ion source was produced via target normal sheath acceleration from Au foils having a thin layer of D2O ice at the rear side, irradiated by sub-petawatt laser pulses (∼200 J, ∼750 fs) at peak intensity . The neutrons were preferentially produced in a beam of ∼70 FWHM cone along the ion beam forward direction, with maximum energy up to ∼40 MeV and a peak flux along the axis for neutron energy above 2.5 MeV. The experimental data is in good agreement with the simulations carried out for the d(d,n)3He reaction using the deuteron beam produced by the ice-layered target.